This invention relates to telephone systems and, in particular, to telephone systems adapted to provide telemetering of equipment at a subscriber's location.
Telemetry systems are known in the art in which entities, particularly, utility companies, are provided access over the public switched telephone network ("PSTN") to entity equipment (e.g., utility meters) at a subscriber location for the purpose of monitoring and accessing this equipment. In a telemetry system, a telemetry interface unit ("TIU") is provided at the subscriber location and attached to the subscriber loop of the telephone system and to the equipment to be monitored or accessed.
The telephone system is then adapted such that it can communicate messages to and from the TIU. This communication process is initiated by an alert message sent by the telephone system to the TIU. The TIU responds to the alert message with an acknowledgement message which may include a preselected telemetry interface unit identifier ("TIUID"). The acknowledgement message indicates that the TIU is in circuit with the telephone system and is ready to conduct an equipment read or control, as the case may be.
Telemetry systems of this type have recently been proposed in which the telephone system is configured so that the messages between the system and TIU are communicated over the normal switch fabric without ringing occurring at the subscriber location. In this type of telemetry system, the telephone system is provided with a central office service unit ("COSU") which communicates with the monitoring entity. The COSU then controls the switching network in the telephone system in response to requests made by the monitoring entity. This control is effected so that a TIU at a subscriber location is brought into the telephone system with ringing suppressed. Accordingly, the telephone equipment at the subscriber location does not ring and operation of the telemetry system does not create a disturbance at the subscriber location. Systems of this type are disclosed, for example, in U.S. Pat. Nos. 5,189,694 and 5,243,644.
An improved telemetry system using suppressed ringing is described in U.S. patent application Ser. No. 07/995,031, filed Dec. 22, 1992, and assigned to the same assignee hereof. In the telemetry system of the '031 application, the telephone system is adapted to further include control routines which automatically account for different subscriber loop types in making the suppressed ringing connections and which generate telemetry system information by correlating certain monitoring entity and telephone system data based on TIUID information. In the system of this application, the computer of the monitoring entity interfaces with a telemetry network access computer ("TNAC") of the telephone system which, in turn, provides control of the COSU to carry out the control routines.
In the above telemetry systems, when equipment at a subscriber location is to be brought into the telemetry system, an installer is dispatched to the subscriber location to install a TIU and to connect it into the telephone system and to the equipment to be monitored or controlled. To verify that this connection has been satisfactorily completed, the installer must place a call to the monitoring entity and request that the entity computer carry out an "install" or "initial" read. The entity computer will then, using the procedures outlined above, initiate an initial read through the telephone system. If this initial read is satisfactory, the installer is advised that the installation has been verified. The installer can then proceed to the next installation.
In order to initiate the above verification procedure, the monitoring entity must know or be given the telephone number of the subscriber location. Often this information is not available to the installer requesting the initial read. The installer must then try to locate the number and, if the number cannot be located, may have to dispense with the verification procedure and return to the subscriber location on another day. This often delays the installation and is a waste of manpower and time.
It is, therefore, a primary object of the present invention to provide a telemetry system in which the procedure for verifying installation of a TIU at a subscriber location is improved.
It is a further object of the present invention to provide a telemetry system in which the procedure for verifying installation of TIU at a subscriber location is simplified for the installer.